Chronic obstructive pulmonary disease (COPD) is a group of lung diseases that block airflow and make it difficult to breathe.

The prevalence of depression and anxiety is approximately 40 per cent in COPD patients while the corresponding figure is less than 10 per cent in the general population, the study said.

But, the results suggested that in patients with COPD, higher levels of physical activity could lessen the risk of developing anxiety by 11 per cent and that of depression by 15 per cent.

"In COPD patients, those with high physical activity are less likely to develop depression or anxiety over time," said Milo Puhan from University of Zurich, Switzerland".

The study has particular significance since mental disorders are common in patients with COPD," Puhan added Physical activity promotion programs could be considered to lower the burden of mental disorders in COPD patients, the researchers suggested.

Conversely, low physical activity could increase the risk of other highly prevalent health conditions such as cardiovascular, neurological, hormonal, musculoskeletal, cancer, and infectious diseases in patients with COPD.

For the study, the team included 409 patients from primary care practice in the Netherlands and Switzerland. The researchers assessed physical activity using the Longitudinal Ageing Study Amsterdam Physical Activity Questionnaire at baseline and followed patients for up to five years.

The study was presented at 2016 European Respiratory Society (ERS) International Congress in London, recently.